The goal of this project is to develop a new microarray platform for performing high-multiplexed analysis of RNA and DNA without chemical modification of target molecules for detection. The main innovation of the proposed approach is the use nanometer-size particles, which carry electric charges and are capable of binding to non-modified target molecules on microarray. This new approach eliminates labeling bias and increases accuracy of RNA and DNA analysis. The approach also significantly reduces time and cost of analysis and allows inexpensive equipment to be used for highly sensitive detection of DNA and RNA on high-density microarrays. [unreadable] [unreadable] In Phase I the proof-of-principle of the proposed approach was demonstrated by comparing results of proposed detection approach and conventional fluorescent microarrays. Application of the proposed microarray system was demonstrated for differential gene expression analysis of normal and ionomycin-stimulated T- cells. In Phase II the system will be further optimized for compatibility with main brands of microarray products and validated for gene expression analysis and microbial genotyping through collaboration with research groups at academic institutions. [unreadable] [unreadable] Achieving the proposed goals of technical performance, simplicity and cost efficiency will provide critical breakthrough and establish a new standard in microarray field. The proposed microarray platform can be implemented in a number of new commercial products, which can find broad application in biomedical research, clinical diagnosis, environmental control, bio-defense, and other areas, which require detection, recognition, and quantification of biological agents.The goal of this project is to develop a new microarray system for gene expression analysis of total RNA without labeling and reverse transcription to cDNA. The proposed microarray platform is the only microarray sytem on market, which is capable of high- multiplexed analysis of DNA, RNA and proteins without chemical modification of target molecules. With the recent reports of using microarrays in clinical tests for tumorogenesis and prognosis of a chemotherapy outcome, introducing an advanced and inexpensive microarray platform will find broad applications in cancer research, developmental genetics, clinical diagnosis, drug discovery, toxicogenomics, and environmental analysis in more than 1,800 clinical laboratories and 45,000 of life science research laboratories in US alone. [unreadable] [unreadable] [unreadable]